Section 5.1: Why Verify?

Remember that the ultimate goal behind implementing homeowner BMP programs is to improve local water quality and watershed health. Ensuring the practices and behavior changes produced as a result of your program are maintained over time will validate your organization’s efforts and be useful in securing funding for future efforts. BMP performance verifications confirm that the BMPs have been properly installed and continue to function correctly. There are a number of methods to verify BMPs. The technique used for your program will depend on your organization’s available resources and the outcome(s) you desire from the verification process.

BMP Initial Verification

This verification is performed to initially verify that the BMP was installed correctly, is in the correct location, meets or exceeds the BMP design standards, and will function as designed. Inspection should occur shortly after installation is complete, and ideally during a runoff producing rain event. This method confirms the BMP functions correctly.

BMP Performance Verification

This verification is performed periodically to ensure the BMP still exists and is still providing the pollutant reduction it was originally designed to achieve. Although the average frequency for this inspection is 5 years, the frequency can range greatly and is better described in section 5.4 of this chapter.

There are several reasons a residential stormwater BMP needs to be verified. If a locality or watershed organization offered incentive money for the BMP installation, they need to confirm that the proper practice was installed in the correct location, per the design, and is functioning properly before the incentive reimbursement is provided to the property owner. The entity financing the project needs to verify that their funding was used consistently with the funding agreement.

Section 5.2: Verification Methods

Verification methods will depend on your program needs. For instance, a locality seeking stormwater reduction credits in the Chesapeake Bay Program Model may desire a more thorough verification process that may include on-site inspections during construction, photo documentation, a BMP Initial Verification, and periodic BMP Performance Verifications over the life of the BMP. Alternatively, a non-profit with fewer resources, simply attempting to improve local water quality, may only require post-installation photos with specific quantifiable measurements included. Regardless of method, it is important to verify that a BMP was installed correctly and the information gathered/reported is consistent from project to project.

BMP inspection and verification can be done by anyone with proper training. The remainder of this section describes the main criteria to be checked for various homeowner BMPs following installation. It is best to complete the post-construction BMP Initial Verification following a storm event, so any functional problems can be observed with the BMP under operational conditions.

See the RiverWise Communities Manual for documentation and examples of BMP visual indicators.

Section 5.3: Personnel

Another important component of the verification process is the personnel and resources required to conduct the work. Some programs may use volunteers such as Master Gardeners to verify the BMPs, while others may have sufficient staff resources to do the job. Both personnel methods have advantages and disadvantages, and the choice should be determined by organizational resources available.

At this time there is no Chesapeake Bay watershed-wide training certification that qualifies an individual to verify residential BMPs. There are a number of local and watershed training programs that cover what is necessary to conduct the verification. Those training programs include:

Any of these training programs provide verifiers with the tools and information to take reliable measurements and collect consistent data. Your organization may conduct additional training to be confident that the Performance Verifications will meet both quality assurance and quality control (QA/QC) standards.

Section 5.4: Frequency

BMP verification is not a one-time task. Following an initial inspection during construction and the BMP Initial Verification (discussed in Section 5.2 of this chapter) the BMP will need to be monitored and maintained for the life of the practice. After a certain number of years, depending on the purpose of the practice, the BMP will need to be verified routinely. If at some point the BMP is not verified or is observed to be not functioning correctly, the credited pollutant reduction may be nullified.

Every 3-10 years (a maximum of 5 is recommended) each BMP should undergo a BMP Performance Verification. The frequency of verification will depend on the program. A Phase 1 MS4 community may be required to report the BMP verification every 5 years. On the other hand, a local watershed group may want to conduct the Performance Verification every year or may be able to do so only every ten years. First determine why you are conducting the verification, and then you can best determine what frequency is most appropriate and allocate your resources accordingly. Make sure to check with your locality for up-to-date approved methods and guidance for BMP verification. Also, you can visit the Chesapeake Stormwater Network’s Urban Stormwater Work Group web page for the latest information about BMP credits and verification (see

Section 5.5: Project and Tracking

Stormwater runoff from private properties remains one of the most difficult and expensive sources of Chesapeake Bay pollution to control. Small-scale residential stormwater BMPs are most often voluntarily installed by property owners but are rarely effectively tracked at the local level by county and/or municipal agencies. Under the current Chesapeake Bay TMDL, water quality treatment practices must be counted and tracked to receive a nutrient and sediment reduction credit. However, few incentives have been provided to support investment in these small-scale, non-permitted stormwater BMPs. The ability to count, track, certify and aggregate these BMPs will validate additional quantifiable water quality benefits across the watershed.